Engines are frequently over-sized in order to provide an anticipated maximum power requirement. However, this results in the engine being run under light loads, that is, under 50% of their rated loads for extended periods of operation. However, diesel engines have a shorter life, increased maintenance and increased air pollution when run at light loads. Diesel engines running at light loads have incomplete fuel combustion, excess fuel washes the cylinder, dilutes the oil and, causes carbon buildup in the engine requiring greater maintenance and repair and shortens the engine life.
The present invention is directed to a method of and an apparatus for improving the operation of a diesel engine at light loads, but which will not adversely affect the operation of the engine at higher loads.